The kings and queens of London’s lesser-known royal family gathered outside a church in Covent Garden on a recent Sunday afternoon dressed in their sparkly finery.

But their jewels of choice were not diamonds or rubies. They were buttons made of mother-of-pearl that covered their jet-black suits and hats in intricate patterns, sewn by hand into elaborate designs that glitter in the sunlight.

These are the Pearly Kings and Queens of London — keepers of a tradition that began in the Victorian era, was passed down through generations of families and became a symbol of the city’s working-class, Cockney culture. They see themselves as custodians of a waning way of life, which they carry on by singing Cockney songs, sharing Cockney stories and, crucially, collecting money for good causes.

Modern pearlies, grouped by geographic area of London, have organized themselves into a few charitable groups and, like the better-known royal family, have at times feuded. But the pearlies argue over which group is the rightful caretaker of the pearly legacy.

Once a month, some pearlies rattle blue plastic buckets to collect charity donations at Covent Garden, a former market turned tourist draw, in London’s West End.

“Most Londoners know about the Pearly Kings and Queens,” said John Walters, 75, who holds the title of Pearly King of Finsbury, an area of north London. “I had an elderly lady come up here and she grabbed hold of me and she started crying and said, ‘I’m so pleased to see you’re still around.’ She said, ‘You are London.’”

Tourists, though, are often pleasantly surprised to encounter them.

On a bright March morning, Mr. Walters and Clive Bennett, 68, the Pearly King of Woolwich, in the city’s southeast, were approached by a group of young women — one wearing a “bride to be” sash — who asked for a photograph. The men, in Cockney accents, instantly broke into a rendition of “Get Me to the Church on Time” from “My Fair Lady” as the women erupted in laughter and threw a few pounds into their buckets. The men tipped their flat caps.

“It’s a real honor to be able to do something like this actually, and it’s fun,” Mr. Bennett said. “You meet all sorts of people.”

He was invited to take part in the opening ceremony of the 2012 Olympics and took part in events on the sidelines of Queen Elizabeth II’s jubilee and funeral.

The over-the-top outfits that the pearlies are known for — with the back of their clothing bearing their august titles in bold lettering — are as peculiar as they are eye-catching, with feathers, shine and patterns assaulting the eyes. The idea for the finery grew from the tradition in Cockney culture of thumbing noses at London society’s disdainful view of the lower classes.

For Mr. Bennett, and many others, being a pearly is a family affair. His wife, Kim, 66, is a Pearly Queen and his daughter and grandchildren take part in fund-raising events, as well, under the title of Pearly Princesses and Princes.

Like most royal families, pearlies typically inherit their titles or marry into the tradition. But others, like the Bennetts, have been invited in because of their commitment to community work and charity.

“Today, there is a need for us now more than ever, ” Ms. Bennett said, as she pointed to the inflationary pressures on many local communities.

Henry Croft — an orphan and a London street sweeper — is considered the first Pearly King. In the late 1870s, he became known for covering his clothing with mother-of-pearl buttons to draw attention as he collected money for hospitals and orphanages.

Mr. Croft was said to have taken his fashion inspiration from costermongers, who were roving traders selling fruit, vegetables, fish and produce on the streets of east London, a working-class area that developed its own distinct accent and vocabulary riddled with rhyming slang, known as Cockney.

The costermongers sewed buttons onto their clothes to distinguish themselves and to mimic the rich, according to the Museum of London. These coster communities would elect a leader in their local area to keep the peace and collect money to support fellow traders down on their luck.

“If someone’s fruit went off, or the donkey was ill, or something like that,” said Mr. Bennett, describing how the costermongers would have a singalong and pass around a bucket for donations. “I think that’s where Henry Croft got his whole ethos from.”

But Mr. Croft took his pearly suits and generosity to a new level, putting on his dazzling button suit as he gathered money for the poor and the sick.

Others soon joined him. At the time of Mr. Croft’s funeral in 1930, dozens of pearlies from across London joined the cortege to honor him, decked out in their buttoned glory.

While London lore holds that to be a true Cockney, a person must be born within earshot of Bow Bells, which ring from St. Mary-le-Bow church in east London, pearly titles are now held by people from communities across all of London’s boroughs.

While some pearly traditions have shifted, the rules on the buttons themselves have stayed consistent: They must be true mother-of-pearl, not imitation. Generally, they are passed down through families.

“A lot of the buttons are over 100 years old on there,” said David Hemsley, 60, describing the jacket he inherited from his father.

In Covent Garden, after a few hours of cheekily delivering rhyming Cockney slang to curious crowds and singing old tunes with gusto while collecting donations, the pearlies make their way into the nearby St. Paul’s Church to hold their monthly meeting.

“Come on then, let’s go!” Doreen Golding, 83, the Pearly Queen of Bow Bells and the Old Kent Road, shouted to the group as she led the way to the church vestry.

As the chairwoman of London’s Pearly Kings and Queens Society, Ms. Golding was honored by the late queen for her charity efforts. She said the pearlies would continue to wear their buttons and keep up their charitable giving for as long as there was a need.

“I get upset when someone says, ‘Oh, are you still around? We didn’t think there was any more of you left,’” Ms. Golding said with a laugh. “And I think, ‘Now hang on, open your bloody eyes and look, we are here!’”